Switching apparatus employing fuse as movable contact and having safety features



g- 2, 1966 R D. CLARK, JR., ETAL 3,264,433

SWITCHING APTARATUS EMPLOYING FUSE AS MOVABLE CONTACT AND HAVING SAFETYFEATURES 8 Sheets-Sheet '1 Filed Nov. 7, 1962 51-}? L3 LOAD Aug. 2, 1966R. D- CLARK, JR. ETAL 3 SWITCHING APPARATUS EMPLOYING FUSE AS MOVABLECONTACT AND HAVING SAFETY FEATURES Filed Nov. '7, 1962 8 Sheets-Sheet 2Fig.2.

WITNESSES lNVENTORS Russell D. Clork,Jr. 2Q; @FMJW 8 Charles J. Mahler3,264,433 FUSE AS MOVABLE Y FEATURES 8 Sheets-Sheet 3 R. D. CLARK, JR.ETAL SWITCHING APPARATUS EMPLOYING CONTACT AND HAVING SAFET Aug. 2, 1966Filed Nov. 7, 1962 \\\\\r I O 0 944 5 m. m m Zn 9 ll 3 Fig.3.

Aug. 2, 1966 R. D. CLARK, JR. ETAL 3,264,433

SWITCHING APPARATUS EMPLOYING FUSE AS MOVABLE CONTACT AND HAVING SAFETYFEATURES Filed NOV. 7, 1962 8 Sheets-Sheet 4 i Q 33 333 334 3,30 3- 82 Ir 39 7 11 340 V7 3 I {j I l ass I I86 0 2|o O I L6;

"I is 202 O H I22 I77 |os\ zqs r l use |24 H206 ,/L/ 0 I 144 I4 L 5% nor. 1 I75 4 Fig.4.

3,264,433 VABLB g- 2, 1966 R. D. CLARK, JR. ETAL SWITCHING APPARATUSEMFLOYING FUSE AS MO CONTACT AND HAVING SAFETY FEATURES 8 Sheets-Sheet 5g- 1966 R. D. CLARK, JR.. ETAL 3,264,433

APPARATUS EMPLOYING FUSE AS MOVABLE SWITCHING CONTACT AND HAVING SAFETYFEATURES 8 Sheets-Sheet 5 Filed NOV. '7, 1962 Fig.9.

4 6 T66 Is g- 1966 R. D. CLARK, JR. ETAL 3,264,433

SWITCHING APPARATUS EMPLOYING FUSE AS MOVABLE CONTACT AND HAVING SAFETYFEATURES Filed Nov. 7, 1962 8 Sheets-Sheet '7 Fig.l0.

Aug- 1966 R. D. CLARK, JR.. ETAL 3,264,433

SWITCHING APPARATUS EMPLOYING FUSE AS MOVABLE CONTACT AND HAVING SAFETYFEATURES Filed NOV. 7, 1962 8 Sheets-Sheet 8 United States PatentSWITCHING APPARATUS EMPLOYING FUSE AS MOVABLE CONTACT AND HAVING SAFETYFEATURES Russell D. Clark, In, East Aurora, and Charles J. Mahler,

Fairport, N.Y., assignors to Westinghouse Electric Corporation,Pittsburgh, Pa., a corporation of Pennsylvania Filed Nov. 7, 1962, Ser.No. 235,940 20 Claims. (Cl. 200-114) This invention relates to switchingapparatus and more particularly to line starters of the type having inseries in the power circuit, a disconnect or isolating switch, a fuse,and main or power contacts of a contactor. Such a switching apparatus isgenerally disclosed herein and is also disclosed and claimed in the U.S.patent application, Serial No. 235,938, filed by Alfred W. Hodgsonconcurrently herewith, and assigned to the same assignee. Particularfeatures of a fuse mount for pivotably supporting one end of a powerfuse disclosed herein (FIG. 6) are claimed in U.S. patent application,Serial No. 235,939, filed concurrently herewith by Alfred W. Hodgson andRussell D. Clark, Jr., and assigned to the same assignee. Particularfeatures of a fuse clip at the other end of the fuse (FIGS. 6, 7, and 8)are claimed in U.S. patent application, Serial No. 399,119 (a divisionhereof).

An important object of this invention is to achieve size reduction inswitching apparatus. Aside from manufacturing and space economies,reduced mechanical size is conductive to longer life of operating partssuch as the contactor. Safety of mechanical interlocks is improved withsmall levers and other movable lock elements having more positive actionthan larger parts. With smaller components and structure, maintenance iseasier in spite of a smaller enclosure. Thus an over-all object of theinvention is switching apparatus having for particular power capacity,minimum dimensions, weight, and manufacturing costs, but at the sametime providing increased safety, reliability, and ease of maintenance.

In accordance with one embodiment of the invention, the above objectsare achieved by a novel over-all and detailed structural arrangementwherein a contactor, power fuse, and disconnect, structurally flow intoeach other to provide a compact integral unit. In this embodiment, theapparatus is disposed in an enclosure with a door, and the power fuse isrockably mounted at one end, while the other end is coupled to a movablecarrier which rocks the fuse into and out of contact with a line contactmember, thus forming a disconnect or isolating switch. Also in thisembodiment, an externally operable mechanism moves the carrier.

An important phase of the invention is directed to various mechanicalinterlocks which provide the following features: The carrier is lockablein position in response alternatively to operation of the contactor orto opening of the door; the isolating switch cannot be closed with thedoor open; and the door cannot be opened with the isolating switchclosed. A shutter moves between the isolating switch contacts inresponse to movement of the carrier.

It is therefore an object of the present invention to provide switchingapparatus with novel safety arrangements including mechanical interlocksand automatic shutter.

Another object of the invention is to provide switching apparatus in anenclosure with a door wherein novel safety interlocks prevent opening ofthe door when switch contacts are closed, and which prevent closure ofthe switch contacts when the door is open.

A further object is to provide novel mechanism for operating a movablefuse, into and out of contact with a line contact.

across one phase of the main power lines.

3,264,433- Patented August 2, 1966 Other and further objects andadvantages will become apparent from the following description taken inconjunction with the drawings, wherein a preferred embodiment of theinvention is illustrated.

In the drawings:

FIGURE 1 is a schematic diagram of an example of a circuit for switchingapparatus built in accordance with one embodiment of the invention anddescribed herein;

FIGURE 2 is a front view with parts broken away of switching apparatusincorporating features of the invention;

FIGS. 3 and 4 are sectional views taken generally along the line III-IIIof FIGURE 2, with some parts shown in full. FIG. 3 shows the apparatusin the OFF position while FIG. 4 shows the apparatus in the ON position;

FIG. 5 is a perspective view looking at the fuse clip carrier from thetop and illustrating the slidable mount- .ing of the carrier and thecooperative relation between the carrier and a shutter along the backwall which is interposed between the switching apparatus and active lineelements in the off position of the apparatus;

FIG. 6 illustrates details of upper and lower fuse clips included in theapparatus of FIG. 3;

FIG. 7 shows a detail of the upper fuse clip in FIG. 6;'

FIG. 8 illustrates an alternative form of the detail in FIG. 7;

FIGS. 9 and 10 are views taken generally along the line IX-IX of FIGURE2 showing the right sides of the disconnect and con-factor units, andillustrating details of safety interlocks in various positions. In FIG.9 the apparatus is shown in the OFF position, while in FIG. 10 theapparatus is shown in the ON position. Although these views show thedisconnect and contactor units as they are related in the cabinet, thecabinet itself is not shown in FIGS. 9 and 10, except for a fragment ofthe cabinet door seen in FIG. 9;

FIGS. 11 and 12 are views illustrating details of the operating handle,handle housing, and bearing plate arrangement, both views looking at thebackside of the bearing plate; and

FIG. 13 is a view illustrating an alternative arrangement for pivotablymounting the lower end of the fuse.

Circuit Included in the diagram of FIG. 1 is a power-operated maincontactor 20 with power contacts .22 to connect three-phase load linesL1, L2 and L3 to conductors A, B and C, which are normally connected tomain supply lines S1, S2 and S3, through a disconnect or isolatingswitch 24 formed in accordance with the invention by a uniquearrangement of main fuses 26 and sets of complementary disconnectcontacts 28.

Contactor 20 includes an electromagnetic operator 30, which is energizedby a rectifier 32 in response to the operation of a normally biased openpush button start switch 34. Closure of the start switch energizes arelay 3'6 whose normally open contacts -38 and 40 respectively connectthe output of rectifier 32 to the operator 30 and the input of therectifier to the secondary 42 of a stepdown transformer 44, whoseprimary 46 is connected The input to primary 46 includes fuses 48 andstab type disconnects 50. The electromagnetic operator of relay 36 isenergized from the transformer secondary 42 through a circuit whichincludes a double pole, double throw switch 52, normally in the positionshown, fuses 54, a normally closed stop switch 56, and a normally closedthermostatic switch 58. Included in the output circuit of rectifier 32are the normally open contacts 38, male female type plug disconnects 60,and an adjustable resistor 62 which may be adjusted when needed tocompensate for aging of the rectifier cells in rectifier 32. A hold orlatch circuit 64 load lines.

is shunted across the start button 34 and includes malefemale plug typedisconnects '66 and normally open contacts 68, which are operated toclose the circuit across the start button when contactor 20 is operated,thereby holding relay 36 and consequently contactor 20 in the operatedcondition.

The thermostatic switch 58 is an overload switch and responds tooverload of the load lines as manifested in the heating of resistors 70and 72, energize respectively from current transformers 74 and 7 6through intermediate transformers 7 8 and 80. Current transformers 74and 76 are coupled to the load lines.

Cabinet and general disposition of components therein lating switch unit92 and a main contactor unit 94, each being slidably removable from thecabinet. The isolating switch 24 .and its operator are included in theunit 92 while the main contactor 20 is included in the unit 94. Thepower fuses 26 are supported by both units 92 and 94. Thus the mainpower components are located in units 92 and 94. Thus, the main powercomponents lying within the dashed line enclosure 95 (FIG. 1) arelocated in units 92 and 94 (FIG. 2).

The apparatus within the dashed line enclosure comprising the contactor20, the isolating switch 24, and the power fuses 26, may be designatedthe main power apparatus, while that outside the dashed line enclosuremay be referred to as the auxiliary equipment.

Referring again to FIG. 2, it is seen that the current transformers 74and 76 are located in the lower section of the cabinet 90 below thecontactor unit 94, while most of the rest of the auxiliary equipment islocated in the space on the right side of cabinet 90 formed between theright wall 95 of the cabinet 90 and units 92 and 94. Most of the wiringbetween the components is not shown in FIG. 2.

Although the back of cabinet 90 is shown generally open to provideconvenient access for connections to main power and load lines, it willbe appreciated that either the top or the bottom of the cabinet may beapertured instead of the back for the receipt of supply and Cabinet 90is provided with a frontal opening 97 through which units 92 and 9'4 areaccessible and removable. When the isolating switch unit 92 is properlylocated in the cabinet, a portion of opening 97 is covered by a frontpanel 98 attached to and forming a part of unit 92. The rest of theopening 97 is coverable by by main door 100 and an auxiliary door 102,both hinged to the right wall 95 of cabinet 90.

Main contactor unit The main contactor unit 94 is provided with a frame104 formed from side walls 106 and 8 held in rigid spaced relation bycross pieces 110 and 112 whose ends are secured to the side walls of theframe. In a particular example, the cross piece 110 was made of stronginsulating material to improve the voltage rating of the apparatus.While the side walls and the front cross piece 110 of this frame arevisible in FIG. 2, the back cross piece 112 is visible only in FIGS. 3,4, 9 and 10. The cross piece 110 is also visible in section in FIGS. 3and 4. One or the other of the side walls may be seen in each of FIGS.3, 4, 9 and 10.

At their lower edges, walls106 and 108 are provided with inturnedflanges 114 and 116 for seating on and slidably engaging a pair of rails118 and 120 secured to the cabinet floor and extending from front toback.

Since a three-phase example is shown, contacts 22 comprise three sets ofrelatively movable, mutually engageable, complementary main contacts,one set per phase line. Thus the contactor has three sets of maincontacts and attendent blowout coils and are chutes. In FIG. 2, detailsfor only one set, C, are shown, while in FIGS. '3 and 4, the set shownin detail is that of B. However, all sets are the same, being duplicatesof one another.

Each set of contacts 22 includes a fixed contact 122 (FIGS. 3 and 4) anda movable contact 124. Contact 122 is secured to a conductive bracket126 which extends from and is an integral part of the conductive base128 of a fuse mount 130 for rockably supporting the lower ferrule orcontact end 131 of a main power fuse 26. By Way of example, the fuseshown is an elongated tubular type having an insulating casing 132 andend contacts such as ferrule type terminals 131 and 163 coupled to theopposite ends of the fuse, the end contacts 131 and 133 being connectedto an internal fusible element. The fuse mount 130 is carried by aninsulating support 134 iixed to the back cross bar 112 which is providedwith an aperture 135 for the passage therethrough of a bushing portion136 of the insulating support 134. The insulating support 134 has upperand lower side walls 138 and 139 to provide insulative shielding betweenphases.

Movable contact 124 is carried by an assembly 140 clamped with anintervening insulating sleeve 142 to a contactor operating shaft 144 forrotation therewith. More specifically, contact 124 is secured to aspring- "loaded arm 146 pivoted to a member 148 that is clamped torotate with shaft 144. A bias spring 150 urges the arm 146 fonward toseat the contacts when they are operated (closed). When the contacts arein an unoperated position (open) the arm 146 is stopped by an abutment152 on member 148. The spring loading and pivoting of arm 146 provides arolling contact force when the contactor shaft 144 is rotated to closethe contacts. The insulation 142 is part of insulative molding aroundthe shaft 144, which molded insulation includes annular flanges 1 54 onopposite sides of member 148 to provide insulation between phases.

Each phase section of the contactor is provided with a blowout coil andassociated arc chute 162. The blowout coil is located forward of boththe fuse 26 and the set of main contacts 22, while the arc ch-ute islocated between the blowout coil and the fuse. This provides anextremely compact arrangement which permits convenient access and allowsthe arc chute outlet to be angled outward to steer the arc and gasesaway from sensitive areas. Compactness is served by the generallyL-shaped pattern in which the fuse 26, the contactor contacts 1224124and the blowout coil 160 are arranged. The fuse is along the leg of theL, the blowout coil at the toe of the L, and the set of contacts isalong the foot of the L and back of the toe. In FIGS. 3 and 4, theL-pattern appears in reverse.

The blowout coil 160 encircles a laminated iron core 164 from which itis insulated by an insulating sleeve 166 which supports the core (FIG.3). The sleeve 166 is supported at opposite ends by brackets 168 and 170secured to an irregularly shaped insulating member 172 which is carriedby and straddles the cross bar 110. The ends of the sleeve 166 areshouldered and snugly pass through apertures in the upper ends ofbrackets 168 and 170 so that the ends of the sleeve extend beyond thebrackets to provide a bearing surface for side plates of the arc chute.Insulating member 172 has flanges 174 and 175 on opposite sides of theblowout coil mounting to provide insulation between phases. A pair ofarc chute retaining bolts 176 and 177 are threaded into opposite ends ofthe core 164.

The ends of the blowout coil 160 are bolted to heavy conductiveterminals 178 and 179 secured to opposite sides of the insulating member172. A flexible conductive strap 180 connects the terminal 178 to themovable contact arm 146. Since it is phase B which is shown in detail inFIGS. 3 and 4, terminal 179 is connected to load line L2 through aconductive strap 181 supported by an insulator 182 secured to thecabinet 90. It should be noted that in phases A and C, the respectiveterminals 179 are connected to the strap primaries of transformers 76and 74, the other ends of these primary windings being connected to loadlines L1 and L3, respectively. In FIGS. 1 and 2 the terminals 179 of therespective phases are represented by D, E and F. It should be noted thatthe connections at terminals D, E and F are made only after thecontactor unit 94 has been inserted in the cabinet 90.

The are chute 162 is of the spaced plate type having a group of parallelspaced insulator plates 183 bounded by insulating side walls 184 and186. At opposite ends of the stack of plates 183 there are provided apair of conductive arc horns 188 and 190. The lower end of arc horn .190has attached thereto a conductive blade 192 which is received andfrictionally gripped by a conductive spring clip- 11194 attached tobracket 126. Likewise, the lower end of arc horn 188 is provided with aconductive blade 196 which is received and frictionally gripped by aconductive spring clip 198 attached to terminal 178. Arc horns 188, 190,their respective blades 19 2 and 196, and clips 194 and 198, are made ofconductive material for circuit continuity.

On opposite sides thereof, the arc chute 162 is provided withferromagnetic pole pieces 200 and 202 secured to the side plates 184 and186, respectively. The pole pieces 200 and 202 are provided with slots204 and 206 in which bolts 1% and 1'77 are received to provide a pivotalmounting for the arc chute .162 and easy removal of the arc chute alongthe slot when the are chute is tilted to the left, FIGS. 3 and 4, sothat the arc chute may be removed through the frontal opening of thecabinet. The are chute may be tilted to the left to permit inspection ofthe contacts or for removal of the arc chute as desired. When the arcchute is tilted to the left the are born stabs 192 and i196 disengagefrom clips 194 and 198. The side walls 184 and 186 of the arc chute 16 2are out out at 208 to fit around and ride on the insulating tube 166.Extra insulation around phases is provided by fixed insulating barrierplates 209 and readily removable insulating barrier plates 210 that areslidable in and out of place. Plates 209 are hung from members 404Aattached to a cross bar 400A that is fixed within the isolating switchunit 92.

The are chute is mounted at an angle of approximately 45 to providespace for the power fuse to pivot as required during operation of theisolating switch and also to direct hot exhaust gases from the arc chuteup and forward toward the enclosure door away from energized components.

From the aforesaid description of the structural details and position ofthe arc chute it is seen that the arc chute is pivoted about the blowoutcore center line through the use of a floating blowout core mountingarrangement, to permit removal of power fuses and for inspection ofcontactor contacts and internal parts of the arc chute. The arc chute isproportioned and pivoted in a manner such that no additional clearanceis required within the starter for swinging the arc chute open. Sincethe arc chute swings out of the open cabinet door, the necessity foradditional clearance space within the cabinet for are chute opening orremoval is eliminated, the arc chute is more accessible for inspection,and the operator cannot close the enclosure door and energize thestarter with the arc chute open. It is further apparent that the arechute is supported by its blowout pole pieces which in turn are boltedto the blowout core by means of the open end slotted holes, asheretofore described, so that the arc chute may be removed simply byloosening the blowout core bolts rather than by removing these boltscompletely.

It will be noted that the connector 178, the flexible 5, strap 180, andthe movable contact and contactor arm 146 form a reverse current loopwhich in response to power current through the contacts providesmagnetic forces that react to help hold the contacts closed.

Contact 124 is driven into engagement with contact 122 by rotation ofshaft 144 which is journalled in the side walls 106 and 108 of thecontactor assembly frame 184 and is driven by the electromagneticactuator 30. The latter comprises an electromagnet 220 and an armature222 clamped to contactor shaft 144 (FIGS. 9 and 10), and aligned to beattracted by the electromagnet 220 when the latter in energized byrectifier 32. The electromagnet 220 includes ferromagnetic cores 224 and226 connected by a magnetic yoke 228, around which cores are wound coils229 and 230. Yoke 228 is L-shaped and also functions as a bracket, beingsecured to the side wall 108 of the contactor frame 104 (FIG. 2). Theends of poles 224 and 226 are overlaid by a nonmagnetic shim 231 held inplace by ferromagnetic pole faces 232 and 233 clamped by bolts 234screwed into the cores. The shim 231 provides an effective air gap toreduce armature sticking. Clearance for the heads of bolts 234 isprovided by apertures 235 and 236 formed in the armature 222. In FIG. 9,the electromagnetic actuator 30 is shown deenergized, in which positionthe contactor 28 is unoperated and its contacts are open. When theelectromagnet 220 is energized, the armature 222 is drawn upward as inFIG. 10, thus rotating shaft 144 to force contact 124 into engagementwith the fixed contact 122. This is the operated position of thecontactor. When the electromagnet 220 is deenergized, the main contacts22 are opened by the force of contact spring 150 and the force ofgravity on the armature 222. In this position armature 222 rests againsta stop 237 fixed to the wall 108.

In addition to operating the main contacts to a closed position, theelectromagnetic actuator 30 also when energized, closes the normallyopen contacts 68. Normally open switch contacts 68 are shown in FIGS 9and 10 in the form of a plunger switch 239 having a spring-biasedoperating plunger 240. This plunger is driven from its open (FIG. 9) toits closed (FIG. 10) position by a boss 242 attached to one arm 244 of abell-crank lever 245 movable around a pivot 246 fixed relative to theside plate 188, and having another arm 248 driven from open to closedpositions by the armature 222 of the electromagnetic actuator 30.Coupling between armature 222 and the bell crank arm 248 is effected bya lateral pin 250 fixed to thearmature and having one end disposed inand engaging the walls of a slot 252 formed in the end of the bell crankarm 248. Thus it is apparent that normally open contacts 68 are closedin response to the operation of contactor 20.

It will be seen in FIGS. 3 and 4 that the fuse mount 130, whichpivotably supports the power fuse 26, has conductively attached theretoand integral therewith a contact clip 260 which extends through bushing136 and engages a stab contact 262 when the contactor unit 94 isdisposed in operative position in the cabinet. Stab 262 is mounted on aninsulator 264 carried by an insulator cross bar 266 secured to oppositesides of the back end of cabinet 90. Clip 268 and stab 262 constitutethe disconnect set 50 connected to phase B, stab 262 being connectedthrough a fuse 48 to the primary 46 of transformer 44. It will beappreciated that a similar stab 262 associated with the fuse mount inphase C is connected to the other end of the transformer primary 46through a fuse 48.

Fuse receptacle 130 is provided with a pair of spaced front contactfingers 270 and 272 extending upwardly from the base 128 to frictionallyand conductively engage the contact ferrule 131 of fuse 26 (FIGS. 3, 4and 6). The fuse receptacle 130 is further provided with a rearwardupstanding gripping finger 276 pivoted at its lower end to the base 128and forwardly biased by a spring 289.

As seen in FIG. 4, when the power fuse 26 is in a vertical position, thelower contact ferrule 131 is engaged and forwardly urged by finger 276into forced tight en- The upper ferrule 133 of fuse 26 is held in aconductive fuse clip 286 pivotally suspended from a carrier 288, made ofinsulating material, which is slidably mounted in the isolating switchunit 92 for backward and forward movement in response to an operatinglinkage 290 (FIGS. 3 and 4). In addition to fuse jaws 291, the clip 286is provided with posterior stab jaws 292 for conductively engaging afixed contact in the form of main line stab 294 mounted on an insulatorarrangement 296 carried by cross member 298 secured between the sidewalls of cabinet 90. In the example shown, the clip 286 is a contactdirectly engaging the fixed contact 294. However, since the end contact133 is coupled to the upper end of the fuse, and since the clip 286 isan extension of the end contact 133, the upper end of the fuse is inelectrical contact with the line stab 294 when clip 286 is in contactwith line stab 294. Being in phase B, the line stab 294 in FIG. 3 isconnected to supply line S2.

As shown in FIGS. 6 and 7, clip 286 comprises two similarly shapedcomplementary members 300 and 302,

each having an intermediate shank portion 304 and the fuse jaw and stabjaw end portions 291 and 292, respectively. At their shank portions 304,members 300 and 302 (FIGS. 7 and 6) are pivotally coupled together andto a pivot plate 314 by means of a spring loaded bolt 310 passingthrough oversize apertures 312 formed in members 300 and 302 and anaperture 316 formed in bracket 314. A spring 317 resiliently biasesmembers 300 and 302 toward each other. At their inner faces, members 300and 302 are provided with protuberances 318 about which members 300 and302 can rock with the pivot plate 314 providing the fulcrum. A pin 322affixed to and extending from opposite sides of bracket 314 extendsthrough and engages the walls of slots 324 formed in the intermediateportions of members 300 and 302, thereby maintaining the members inalignment with each other and with the bracket 314.

In the position shown in FIG. 3, the stab jaws 292 are not in engagementwith the stab 294 and the upper fuse ferrule 133 is held in the fusejaws 291 under light pressure. However, in the position shown in FIG. 4,the stab jaws of the clip 286 are in engagement with the stab 294, whichacts as a wedge to drive the stab jaws 292 apart and compress the spring317, thereby increasing the compressive force of the fuse jaws 291 totightly clamp the upper ferrule of the fuse. This compression of thespring increases the contact force on both the stab 294 and the upperferrule of the fuse. When the clip is withdrawn from the stab 294 as inFIG. 3, the elements 300 and 302 are permitted to touch the pivot plate314. In this position the spring force is much reduced, allowing easyremoval of the fuse.

Pivot plate 314 is suspended on a pivot 326 (FIG. 3) carried by abracket 328 attached with bolts 329 to the carrier 288, whereby the clip286 is moved forward and backward together with the carrier 288. Plate314 has a tab 331 and a pin 333 to provide opposite travel limits forclip 286 about pivot 326. From the above description it will beappreciated that the carrier 288 is flexibly coupled to the fuse 26 bymeans of the pivot plate 314, which with pivot 326 provides a flexibleor articulate (movable) joint between the carrier 288 and the fuse 26.

Alternatively, as shown in FIG. 8, the protuberances 318 may beeliminated, and the pivot plate 314 thickened along its extent betweenthe members 300 and 302 to provide sufiicient rocking clearance, thus toallow the elements 300 and 302 to be rocked around the pivot plate as afulcrum. In this arrangement the pivot plate provides a fulcrum at itsrearward edges 320 around which the members 300 and 302 rock when thefuse jaws are forced apart.

As seen in FIGS. 2, 3 and 9, the isolating unit 92 is provided with aframe 330 comprising the front panel 98, a back panel 332 made ofinsulating material, and side plates 334 and 336 rigidly securedtogether in the form of an open rectangle as viewed from the top. Morespecifically, the side plates are secured to angular extensions of thefront and back panels extending from and normal to the front and backpanels. For example, the side panel 334 is bolted to angular extensions338 and 340 extending from the front and back panels respectively (FIG.3). As seen in FIG. 9, the side plate 336 is secured to an extension 342of the front panel 98. The extension from the back panel to which theside plate 336 is secured is not visible in the drawings. The back panel332 is provided with three apertures 343A, 343B and 343C, through whichthe stab jaws 292 of the respective phases are projected and retracted.

Side plates 334 and 336 are provided at their upper edges with outwardlyextending flanges 344 and 346 which slidably bear on rails 348 and 350.,thereby supporting and allowing slidable movement of the isolating unitinto and out of the cabinet. Rail 348 is secured to the left side wallof the cabinet (FIG. 2), while the rail 350 is supported by brackets 352secured to the top and right sides of the cabinet. The side plates 334and 336 are provided with inwardly facing channels 354 and 356 whichprovide guidance and support for the carrier 288 (FIGS. 2 and 5). Morespecifically, channels 354 and 356 are arranged to receive tabs 358,360, and 362 and 364 which are integral with and laterally extend fromthe carrier 288. The lower surfaces of channels 354 and 356 act as railswhich provide support and slidable movement for the carrier 288.

The operating linkage 290 for reciprocating the carrier 288 from one tothe other of its ON and OFF positions, is provided with an adjustableconnecting rod 370 having one end pivotally connected at 372 to thecarrier 288. The connecting rod 370 includes an internally threadedpivot block 374 pivoted at 372 to the carrier 288, an internallythreaded clevis block 376 and an intermediate shank 378 which isthreaded at opposite ends and links the two end blocks 374 and 376. Oneend of the intermediate shank 378 is threaded into and locked withrespect to the pivot block 374 while the other end of the shank 378 isthreaded into but not locked with respect to the clevis block 376. Thusthe clevis block 376 is rotatable around the longitudinal axis of theconnecting rod 370 employing the threaded end of the shank portion 378as a bearing. The clevis block 376 terrninates in a clevis 380 pivotallycoupled at 382 to an arm 384 of a bell-crank shaped switch handle 386.The latter is rotatable about a pivot 388 fixed relative to a handlehousing 390 which is rotatable about an axis generally in line with thelongitudinal axis of the connecting rod 370 when the linkage is alignedas in FIG. 3.

In order to allow coupling between the clevis 380 and the bell-crank386, the front panel 98 is provided with a vertical slot 392 (FIGS. 3,4, 12) through which the clevis block 376 and the crank arm 384 arepassable when moved between the positions shown in FIGS. 3 and 4. Exceptfor a reduced rounded portion 394 the clevis block 376 and the handle386 each have opposite flat sides and a thickness therebetween whichallows movement of these members between the positions shown in FIGS. 3and 4. However, their rotational movement about the general axis of theconnecting rod 370 is blocked by the vertical sides of slot 392 in allpositions of the handle 386 around axis 388, except the position Shownin FIG. 3 (also FIGS. 12 and 13), wherein the 9 reduced rounded portion394 of the clevis block 376 is aligned within the slot 392. In thelatter position, it is apparent that the clevis block 376 may be rotatedand the handle 386 may be rotated around an axis generally parallel tothe longitudinal axis of the connecting rod 370.

Since FIG. 3 shows the clip 286 disengaged from the line stab 294, theisolating switch and its operating elements are in the OFF position inthis figure. Thus the particular position assumedin FIG. 3 by the fusereceptacle 130, fuse 26, clip 286, carrier 288, clevis block 376, andhandle 386, shall be referred to as the OFF position of each of theseelements. On the other hand, in FIG. 4 the clip 286 is fully engagedwith line stab 294, and the isolating switch and all its operatingelements are therefore in the ON position.

Referring now to the OFF position in FIG. 3, the operating handle 386points downwardly and the reduced section 394 of the clevis block 376 isaligned with the slot 392. In order to operate the isolating unit fromthe OFF to the ON position, the handle 386 is moved upward and clockwisearound the pivot 388 until it assumes the position shown in FIG. 4, thatis, its ON position. As the handle 386 is rotated clockwise around pivot388, its arm 384 moves the clevis block 376 and the carrier 288 from thepositions of FIG. 3 to that of FIG. 4. During this movement, carrier 288moves the clip- 286 to the rear and into engagement with line stab 294.During the course of this movement, the upper end of fuse 26 is swung orrocked in a vertical are around a pivot point approximately at thecontact between the lower ferrule 131 and the fuse receptacle 130.

Attached to the isolating unit frame 330 is a ground bar 400A which isengaged by a flat contact spring 402A attached to the bracket 328 whenthe isolating switch is moved from the ON to the OFF position, thusgrounding the upper end of fuse 26 for purposes of safety. Also duringthe movement from ON to OFF position, the upper edge of one fuse jawengages a guide member 404A fixed relative to the frame 330, thereby toforce the fuse jaws down and the stab jaws 292 upward relative to thefuse, thus changing the angle between the axes of the fuse 26 and theclip 286 from substantially 90 to an angle slightly greater than 90.This action moves the stab jaws 292 to a sufficiently upward positionwhere they may be easily viewed through the open door of the cabinet forvisual indication of the open position. Guide 404A also positions clip286 for fuse insertion.

Attached to the front face of the front panel 98, is a bearing plate 395which supports the housing 390 for rotation in the directions of thedouble headed arrow 396 (FIG. 2) around an axis which is normal to panel98 and generally parallel to the path of movement of the connecting rod370. Housing 390 comprises a pair of spaced parallel guide walls 398 and400 (FIGS. 2 and 11) integral with and extending forward from a backportion 402, which is provided with a slot 404 that is aligned with thespace between the guide walls. This slot may also be aligned with theslot 392 in the front panel 98 by rotating the housing 390 to thatposition shown in FIGS. 3, 4, 9, 10, 11 and 12. The axis of the pivot388 around which the handle 386 is rotatable is crosswise of therotational axis of the housing 390. Thus the handle 386 is rotatableabout two axes, that of pivot 388 and that of the housing 390.

Referring now to FIGS. 11 and 12, the back portion 402 of the housing390 includes twin arcuate sections 406 and 408 disposed on oppositesides of the slot 404. Sections 406 and 408 have respective rearwardlyextending arcuate sections 410 and 411 of lesser radius than the parentsections. Thus there are formed between the reduced sections and theparent sections annular shoulders having flat backwardly directed faces414 and 416, respectively. The rearwardly extending arcuate sections 410and 411 are so dimensioned that they are received with a snug butrotatable fit within a generally circular aperture 418 in the bearingplate 395. The upper part of aperture 418 has a slot contour 419 whichregisters with slot 392 in the front panel 98.

The bearing plate 395 has a circular undercut channel 420 extendingradially outward from the edge of aperture 418 and dimensioned toprovide a snug but rotational fit to a pair of generally arcuate plates421 and 422 secured respectively to the arcuate extensions 410 and 411of the housing base 406, thus trapping the undercut lip 423 around theaperture 418. Thus the bearing plate 395 forms a bearing supportcarrying and permitting rotation of the housing 390. Arcuate plates 421and 422 are provided with stop tabs 424 and 426 which freely travel thearcuate extent of radially enlarged segments 428 and 430 of the channel420. The opposite ends of enlarged channel segment 430 and the lower endof enlarged channel segment 428 form abutments to engage the respectivestop tabs thereby to limit the rotation of the housing 390 to (FIG. 12).The position of the housing 390 in FIGS. 3, 4, and 9 to 12 is at onelimit of the rotation, and the position in FIG. 2 and in dot-dash inFIG. 12 is at the other limit 90 away, coun terclockwise.

As seen in FIGS. 11 and 12, the bell-crank arm 384 and the clevis block376 can pass freely through slot 392, when the housing 390 is in theoperative position, i.e., when the housing is aligned with slot 392.However, the dimensions of their rectangular cross sections relative tothe slots are such that when the handle 386 is in the ON position (FIGS.4 and 10), or any position between OFF and ON, the walls of slot 392prevent the clevis block 376 and the bell crank arm 384 from rotatingaround an axis normal to the panel 98, and thereby prevent rotation ofthe housing 390. However, when the handle 386 is in the OFF position,FIGS. 3 and 9, the reduced section 394 of clevis block 376 is alignedwith slot 392, thereby allowing the linkage and handle 386, togetherwith housing 390 to freely rotate within its permissible 90 arc oftravel, for example, to the SAFE position (FIG. 2 and in dot-dash FIG.12). Another result which follows from this arrangement is that when thehousing 390 is in any other position than the operative position(opening 404 of the housing aligned with slot 392 in panel 98), theshoulder 432 between the main body of the clevis block 376 and itsreduced portion 394 overlies the edges of slot 392,. thereby preventingrearward movement of the clevis block toward the back of the cabinet 90.As a consequence, in the SAFE position (FIG. 2 and dot-dash FIG. 12), orin any position between the OPERATIVE and SAFE positions of the housing390, the handle 386 cannot be rotated around pivot 388 to move thecarrier 288 to the ON position.

Housing 390 is provided with an extending portion 440 which blocks theclosed door 100 when the housing 390 is in the OPERATIVE position (FIGS.3, 4, 9 and 10). Thus the door cannot be opened unless the housing 390is rotated to the SAFE position (FIG. 2 and dot-dash FIG. 12). It hasalready been established that the SAFE position can be approached bythehousing only when the handle 386 is in the OFF position, in whichposition the carrier 288 is in the OFF position.

In orderto prevent operation of the handle 386 from the OFF to the ONposition when the door is open, rotation of the housing 390 from theSAFE .to OPERA- TIVE positions is blocked by a spring loaded pin 442based in the lower part of panel 98, and extending across the path ofmovement of the housing 390. When the door is closed, the pin 442 isdepressed against its spring by engagement with the inner face of thedoor. With the door closed, the pin 442 does not impede movement of thehousing 390.

From the foregoing description, it should be apparent that the door 100cannot be opened unless the carrier 288 has been moved to the OFFposition, and that the I 1 carrier 288 cannot be moved to the ONposition unless the door is closed.

The apparatus includes additional and concurrent safety features whichlook the carrier 288 in the OFF position when the door 100 is opened,and in the ON position when the contactor armature 222 is attracted tothe electromagnet 220 to operate the contactor 20 main contacts. Thearrangement for providing these features includes a spring loaded latch446 (FIGS. 9 and 10) rotatable about a pivot 448 fixed to the side plate336 of the isolating switch frame 330. The latch 446 has a detent 450which is continuously and resiliently urged upward toward engagementwith the carrier 288 by a spring 452. In the OFF position of the carrier(FIG. 9), the detent 450 engages a rearwardly inclined face 454 on thecarrier tab 364 through a slot 456 in the channel 356. In the ONposition of carrier 288 (FIG. 10), the detent 450 engages a forwardlyslanting face 458 of the tab 364 through the slot 456. When the carrier288 is moved from the ON position to the OFF position, the slanting face458 cams the detent 450 downward until the OFF position of the carrieris reached, at which time the detent 450 moves into engagement with therearward face 454. In somewhat the same manner when the movement of thecarrier 288 is reversed, the rearward slanting face 454 cams the detent450 downward, and the defeat is held down until the other position isreached.

The latch 446 can be locked in place with the carrier 288 in either theON or the OFF position by moving the upper end of a pivoted lock bar 460under a shoe 462 attached to the latch 446. This position of the lockbar 460 is shown in solid in FIG. 10 and in dot-dash in FIG. 9. In thisposition the latch 446 cannot be cammed downward by the faces 454 and458, thus preventing movement of the carrier 288. The lock bar 460 isswingable about a pivot 464 fixed to the side wall 336 of the isolatingswitch frame 330. A spring 466 continuously urges the upper end of thelock bar 460 toward the rear of the cabinet.

The lock bar 460 is movable into the locking position either in responseto the opening of door 100 or in response to operation of oontactor 20.The arrangement for locking the latch 450 in response to opening of thedoor includes a draw bar 468 having a slot 470 which cooperates with apin 472 fixed to the side plate 336 and extending through the slot toallow a combination of reciprocal and rotational movement of the bar468. The back end of the bar 468 has a hook 474 which is hooked aroundthe back edge of the lock bar 460', so that the lock bar is drawnforward into locking position in response to a forward pull on the drawbar 468.

The forward end of the draw bar 468 is coupled by a pivot 476 to one arm478 of a bell-crank arrangement 480 which includes another arm 482 thatis fixed to rotate with arm 478 around a pivot 484. Bell crank 480 isalso provided with an L-shaped operator arm 486 fixed thereto which inone attitude, that shown in FIG. 9, is engageable by the hooked end of abracket 488 attached to the door 100 (FIG. 9). In case the door isopened, the bracket 488 draws the forward leg of the L-shaped operator486 forward to rock the bell-crank 480 counterclockwise, thereby to drawthe bar 460 forward to lock the latch 446. In this mode, the positionsof the bell-crank 480, draw bar 468, and lock bar 460 are as shown indot-dash in FIG. 9. Since the door is being opened, the carrier 228,perforce, must be in the OFF position.

Stability in the forward and the relaxed positions of the draw bar 468is provided by a spring biased toggle arrangement 490 which has twoovercenter positions respectively coinciding with the forward and therelaxed positions of the lock bar 468. Included in the togglearrangement 490, is a longitudinally resiliently compressible lever 492having one end coupled to the free end of bell-crank arm 482 at a pivotpoint 494. The other end of lever 492 is swingable about a pivot pin 496fixed to the side wall 336 of frame 330. The opposite ends of lever 492are slidably movable to and away from each other by means of anarrangement wherein one end includes a pin which is received slidably ina cylinder socket in the opposite end of the lever, both ends beingresiliently urged apart by a spring 497.

As the door is closed, the end of the hook bracket 488 engages the otherleg of the L-shaped operator 486 (dot-dash in FIG. 9) to rotate the bellcrank 480 clockwise, thereby to relax the bar 468, and allow the lockbar 460 to move back to its non-locking position.

The lock bar 460 is moved to its locking position in response tooperation of contactor 20 by means of an arm 498 fixed to the contactorshaft 144 for rotation therewith, and which arm 498 in response to suchrotation engages the lower end of lock bar 460 thereby to rotate itcounterclockwise into the locking position. The end position of thisoperation is shown in FIG. 10. This looks the carrier 288 in the ONposition whenever the contactor 20 has been operated to close its maincontacts.

A further safety feature is provided by a shutter 500 (FIG. 5) whichcovers the stab apertures 343A, 343B and 343C, in response to movementof the carrier 288 to its OFF position, and uncovers these apertures inresponse to movement of the carrier 288 to its ON position. Theseapertures are uncovered when corresponding cut out areas 501A, 501B and501C of the shutter (FIG. 5) are brought into registry therewith inresponse to movement of the shutter. The back panel 332 is provided withupper and lower slide ways 502 and 504 (FIGS. 3 and 5) which support andguide the shutter 500 for slidab-le movement to the right or left as thecase may be.

The mechanism for moving the shutter 500 is best seen in FIG. 5.Attached to the top of the shutter is a fixed arm 506 having at the freeend thereof a pin 508 which passes through a slot 510 in one arm 512 ofa generally L-shaped lever 514 having a second arm 516 at an obtuseangle with the other arm. The end of arm 516 is rotatable about a pivot518 fixed to a bracket 520 attached to the side frame 336. An upstandingpin 522 fixed to the top of the carrier 288, extends through the slot510 of lever arm 512. The sides of slot 510 are slidably engaged withpins 508 and 522. In FIG. 5, the carrier 288 is shown in the OFFposition, and the stab apertures 343A, 343B and 343C in the back panel332 are covered by the shutter 500. The word SAFE applied to the innerface of the back panel 332 is visible through the shutter apertures 501Band 501C, and may be seen by an opera-tor looking through the door (whenopened).

When the carrier 288 is moved from the OFF position to the ON position(shown in dot'dash in 'FIG. 5), the pin 522 moving rearwardly with thecarrier, cams the lever arm 512 to the right to open the shutter 500,i.e., move the shutter to the right to bring the shutter apertures intoregistry with the stab apertures in the back panel 332. 'It should benoted that less than full movement from the OFF to the ON positions isrequired to open the shutter. The pin 5-22 moves the lever arm 512 tothe dot-dash position shown in FIG. 5 during a fraction of the initialmovement of the carrier 288 from the OFF to the ON position. During therest of the rearward movement of carrier 288, the pin 522 idles throughthe slot. In response to movement of the carrier 288 from the ON to theOFF position, pin 522 during the first fraction of forward motion of thecarrier idles through the slot 510, and during the rest of the forwardmovement of the carrier engages the forward end of the slot wall 510 andpus-hes the lever 514 counterclockwise, thereby moving lever arm 512 tothe left and closing the shutter.

A spring latch 530 (FIG. 9) pivoted around pivot 496 drops into a slot532, provided in the back end of the upper flanged edge of thecon-tractor unit side plate 108, when the contactor unit 94 is drawnalmost all the way out .13 of the cabinet. This feature holds thecontactor unit locked in a partially withdrawn position to allow workand inspection therein if desired. To completely remove the contractorunit 94, the latch 530 is lifted manually out of the slot 532.

An alternative arrangement for rockably mounting the lower end of .thefuse 26 on a support that also carries the fixed contact 122 of thecontactor 20 is shown in FIG. 13. In this figure a conductive tab 282fixed, for example by brazing, to the lower ferrule 131 of the fuse, isattached by a bolt 283 to a hinge member 284 which is rockable around apivot 285 that is fixed to a variation of the fuse mount 130 which issupported by the insulating member 134. A flexible conductor 285A isprovided for improved electrical connection between the fuse ferrule 131and the fixed contact .122. For fuse removal, the single bolt 283 ispulled out to separate the fuse from the hinge member 284 on the fusemount 130. The conductive clip 260 is attached to base 130. Thus, ineach of the arrangements shown in FIGS. 3 and 13, the lower end of thefuse is pivotally carried on the fuse mount 130, whereby the upper endof the fuse is pivota-ble around the lower end of the fuse and ismovable forward and backward in a general- 1y arcuate path.

While any suitable insulating material may be employed to fabricate thevarious parts made of insulation, glass alkyl and glass polyester werefound to be particularly advantageous for the dimensions involved. Forexample, glass polyester was employed for the member 172 .and the phasebanrier plates 209 and 210, while glass alkyd was used for the members134, 142, carrier 288, .and backwall 332.

For an independent check of the start-stop circuits, an alternativeposition of switch 52 will connect fuses 54 to lines 55 which may beconnected to a test voltage source (FIG. 1).

In practice the major units of the apparatus may be assembled asfollows: First, the isolating switch unit 92 is slipped into the cabinet90 .and secured in place by bolts screwed into metal tabs fixed to thecabinet 90. Then the con tactor unit 94, sans fuses, is inserted intothecaibinet, after which connections are made at points D, E and F.Next, the fuses 26 may be fitted into place. Then a plug 540 carryingthe male elements of the connectors 60 and 66 is fitted into itsreceptacle to complete the connections at 60 and 66. Conversely, uponremoval of the fuses 26, opening the connections at D, E and F, andpulling out the plug 540, the units 94 and 92 may be pulled out in thatorder for inspection or repair. The auxiliary equipment outside thedashed box 95 (FIG. 1) stays in the cabinet 90.

While not limited thereto, a practical operating example of thedisclosed apparatus was constructed for 3-phase operation with a ratingof 2500 volts, 180 amperes, 700 horsepower, interrupting capacity150,000 kva., in a unit 22 inches wide, 33 inches high and 24 inchesdeep. An additional 6 inch depth was used as a cable pull box. Becauseof the compact and unique construction, two men were able to handle thesubassemblies [without need of hoists, cranes, dollies, etc.

From the foregoing description, it is seen that the disclosed apparatusprovides novel switching structure including a main power contactor,power fuses, and an isolating switch, with the following features;

(a) dramatic reduction in size;

(b) front door cannot be opened when isolating switch is closed (ON);

(c) isolating switch cannot be closed when front door is opened;

((1) isolating switch cannot be opened when the contactor is operated toclose main contacts;

(e) empty stab jaws of isolating switch are tilted upward to be visiblethrough door when isolating switch is opened; and

(f) when isolating switch is opened, shutter is interposed between stabjaws and stabs, and shutter uncovers indicia visible through door byoperator.

It is to be understood that the herein described arrangements are simplyillustnative of the principles of the invention, and that otherembodiments and applications are within the spirit .and scope of theinvention.

We claim as our invention:

1. Thecombination comprising structure means defining interior space,said structural means having an opening and a door therefor movablebetween closed and open positions, first switch means including. .a setof .contacts disposed within said space and operable between open andclosed circuit positions and first operating means for operating saidcontacts, a fuse disposed within said space and having one endconductively coupled to one of said contacts, means for rockably supporting said one end of the fuse in such manner.

that the other end of the fuse is swingable in opposite directionsaround said one end, first contact means coupled to said other end ofthe fuse and movable therewith, second switch means including said firstcontact means and stationary second contact means in the path ofmovement of said first contact means, a member disposed in said spaceand movable to first and second positions, means for so coupling saidmember to said fuse that movement of the member toits first positionswings said fuse in one direction and moves said first contact meansinto contact with said second contact means, and movement of the memberto its second position swings said fuse in the opposite direction andmoves said first contact means out of contact with said second contactmeans, second operating means coupled to said member and extendingexteriorly of said structure means, said second operating means havingrespective ON and OFF positions for operating said member to itsrespective first and second positions, means for locking said member inits first position in response to said first operating means operatingsaid set of contacts to its closed circuit position, means for lockingsaid member in its second position in response to the opening of saiddoor, :a movable barrier, and means for moving said barrier between saidfirst and second contact means in response to movement of said member toits second position and for retracting said barrier in response tomovement of said member to its first position.

2. The combination comprising structure means defining interior space,said structure means having an opening and a door therefor movable toclosed and open positions, first switch means including a set ofcontacts disposed within said space and operable between open and closedpositions and operator means for operating said contacts, a fusedisposed within said space and having one end conductively coupled toone of said contacts,

means for rockably supporting said one end of the fuse in such mannerthat the other end of the fuse is swingable back and forth about saidone end, first contact means coupled to said other end of the fuse andmovable therewith, second switch means including said first contactmeans and stationary second contact means in the path of movement ofsaid first contact means, a first member disposed in said space andmovable to first and second positions, means for so coupling said memberto said fuse that movement of the member to said first position swingssaid fuse in one direction and moves said first contact means intocontact with said second contact means, and movement of the member tosaid second position swings said fuse in the opposite direction andmoves the first contact means out of contact with said second contactmeans, a mechanism coupled to said member and extending exteriorly ofsaid structure means, said mechanism being movable to respective ON andOFF positions for operating said member to its respective first andsecond positions, said mechanism having interference means preventingthe opening of said door when the mechanism is in its ON position, saidmechanism havaee gaea ing a SAFE position approachable by the mechanismonly when in its OFF position, in which SAFE position said memberremains in its second position and the door is cleared of saidinterference means whereby the door may be opened, means responsive tothe Opening of said door for preventing movement of said mechanism fromits SAFE position, a second member resiliently biased to a firstposition and movable to a second position in response to said operatormeans operating said contacts into their closed position and also inresponse to said door being moved from closed to open position, a latchhaving a lockable latching position in which the latch is locked inresponse to said second member being in its second position, said firstmember being locked in its current position in response to the latchbeing locked in the latching position, a barrier, and means forinterposing the barrier between said first and second contact means inresponse to movement of the first member to its second position and forretracting said barrier in response to the first member moving to itsfirst position.

3. Switching apparatus comprising a first set of switch contactsoperable between closed and open positions, operating means foroperating said contacts, a fuse having one end conductively coupled toone of said contacts, means for rockably supporting said one end of thefuse in such manner that the other end of the fuse is swingable aboutsaid one end, first contact means coupled to said other end of the fuseand movable therewith, a second set of complementary switch contact-sincluding said first contact means and stationary second contact meansin the path of movement of said first contact means, a member which ismovable between first and second positions, means coupling said memberto said fuse for swinging said other end of the fuse in one directionand moving said first contact means into contact with the second contactmeans in response to movement of the member to its first position andfor swinging said other end of the fuse in the opposite direction andmoving said first contact means out of contact with the second contactmeans in response to movement of the member to its second position, andmeans for locking said member in said first position in response to saidoperating means operating said first set of contacts into closedposition.

4. In combination, structure means defining a space, said structuremeans having an opening and a door therefor operable between open andclosed positions, first switch means including a set of contactsdisposed in said space and operable between closed and open positionsand operating means for operating said set of contacts, a fuse disposedin said space and having one end conductively coupled to one of saidcontacts, means for rockably supporting said one end of the fuse in suchmanner that the other end of the fuse is swingable about said one end,first contact means coupled to said other end of the fuse and movabletherewith, second switch means having a second set of contacts includingsaid first contact means and stationary second contact means in the pathof movement of said first contact means, a member which is movablebetween first and second positions, means coupling said member to saidfuse in such manner that movement of said member to said first positionswings said fuse in one direction and moves said first contact meansinto contact with said second contact means, and movement of said memberto said second position swings said fuse in opposite direction and movesthe first contact mean-s out of contact with the second contact means,and means for locking said member in said second position in response toopening of said door.

5. In combination, structure means defining a space,

said structure means having an opening and a door therefor operablebetween open and closed positions, first switch means having a set ofcontacts disposed in said space and operable between closed and openpositions, operating means for operating said contacts, a fuse disposedin said space and having one end conductively coupled to one of saidcontacts, means for rockably supporting said fuse in such manner thatthe other end of the fuse is swingable forward and backward about saidone end, first contact means coupled to said other end of the fuse andmovable therewith, second switch means including said first contactmeans and stationary second contact means in the path of movement ofsaid first contact means, a member which is movable between first andsecond positions, means for so coupling said member to said fuse thatmovement of said member to said first position swings said fuse andmoves said first contact means into contact with said second contactmeans, and movement of said member to said second position swings saidfuse and moves the first contact means out of contact with the secondcontact means, first locking means for locking said member in saidsecond position in response to opening of said door, and second lockingmeans for locking said member in said first position in response to saidoperating means operating said set of contacts to their closed position,said first and second locking means including a common locking element.

6. The combination of an enclosure and switching apparatus mountedtherein, said enclosure having an opening and a door therefore with openand closed positions, said switching apparatus comprising a set ofcontacts operable between open and closed positions, first operatingmeans for operating said contacts, a fuse having one end conductivelycoupled to one of said contacts, means mounting said fuse for pivotablemovement of the other end of the fuse about said one end, first contactmeans coupled to said other end of the fuse and movable therewith,disconnect switch means including said first contact means andstationary second contact means in the path of movement of said firstcontact means, a first member movable to respective ON and OFF positionsand coupled to said fuse for swinging said other end of the fuse in onedirection about said one end and moving said first contact means intocontact with said second contact means in response to movement of saidmember to its ON position and for swinging said other end of the fuse inthe opposite direction about said one end and moving said first contactmeans out of contact with said second contact means in response tomovement of said member to its OFF position, said member being disposedin said enclosure, second operating means for moving said member fromone to the other of its ON and OFF positions, a second member movablebetween first and second positions, means for moving said second memberto its second position in response to said first operating meansoperating said set of contacts to their closed position, meansresponsive to said door being moved from its closed to its open positionfor moving said second member to its second position, a latch having alockable latching position which locks said first member when the latchis locked in the latching position, said latch being locked in thelatching position in response to said second member being in its secondposition, said latch being free of said second member when that memberis in its first position.

7. The combination comprising structure means defining interiorspace,'said structure means having an opening and a door thereformovable to closed and open positions, first switch means having a set ofcontacts disposed in said space and operable between open and closedpositions, means for operating said contacts, a fuse disposed in saidspace and having one end conductively coupled to one of said contacts,means for rockably supporting said one end of the fuse whereby the otherend of the fuse is swingable in opposite directions around said one end,first contact means coupled to said other end of the fuse and movabletherewith, second switch means having a second set of contacts includingsaid first contact means and stationary second contact means in the pathof movement of said first contact means, a member movable to first andsecond positions, means for so coupling said member to said fuse thatmovement of the member to said first position swings said fuse in onedirection and moves said first contact means into contact with saidsecond contact means, and movement of the member to said second positionswings said fuse in the opposite direction and moves the first contactmeans out of contact with the second contact means, a mechanism coupledto said member and having respective ON and OFF positions for operatingsaid member to its respective first and second positions, and lockingmeans comprising a locking element movable to a locking position inresponse to which said member is locked, said element being resilientlybiased away from its locking position, a linkage including a toggle,means coupled to said door for moving the linkage from a first to asecond position in response to opening of the door and from the secondto the first position in response to closing of the door, and meansresponsive to movement of said linkage to its second position for movingsaid locking element to its locking position.

8. The combination comprising structure means defining interior space,said structure means having an opening and a door movable to closed andopen positions which respectively cover and uncover said opening, firstswitch means including a set of contacts disposed in said space andoperable between open and closed positions and means for operating saidcontacts, a fuse disposed in said space and having one end conductivelycoupled to one of said contacts, means for rockably supporting said oneend of the fuse in such manner that the other end of the fuse isswingable in opposite directions about said one end, first contact meanscoupled to said other end of the fuse and movable therewith, secondswitch means having a second set of contacts including said firstcontact means and stationary second contact means in the path ofmovement of said first contact means, a member movable to first andsecond positions and coupled to said fuse for swinging said other end ofthe fuse in one direction and moving said first contact means intocontact with the second contact means in response to movement of themember to its first position and for swinging said other end of the fusein the opposite direction and moving said first contact means out ofcontact with the second contact means in response to movement of themember to its second position, said member being disposed in said space,a mechanism coupled to said member and extending exteriorly of saidstructure means, said mechanism having ON and OFF positions foroperating said member'to its respective first and second positions, saidmechanism including a frame and an operator, said frame being rotatableabout a first axis from one to the other of first and second angles,said frame at said first angle barring said door to prevent openingthereof, said operator being connected to said member and beingsupported by said frame for rotation about a second axis from one to theother of ON and OFF positions corresponding to the ON and OFF positionsof said mechanism, the second axis being transverse to the first axis,said operator being operable to either ON or OFF positions when theframe is at said first angle, means for preventing operation of saidoperator to its ON position when the frame is at the second angle, andmeans for preventing rotation of the frame to the second angle when theoperator is in its ON position.

9. The combination comprising structure means defining interior space,said structure means having an opening and a door movable to closed andopen positions which respectively cover and uncover said opening, firstswitch means including a set of contacts disposed in said space andoperable between open and closed positions and means for operating saidcontacts, a fuse disposed in said space and having one end conductivelycoupled to one of said contacts, means for rockably supporting said oneend of the fuse whereby the other end of the fuse is swingable backwardand forward about said one end, first contact means coupled to saidother end of the fuse and movable therewith, second switch meansincluding said first contact means and stationary second contact meansin the path of movement of said first contact means, a member movable tofirst and second positions, means for coupling said member to said fusein such manner that movement of said member to said first positionswings said fuse in one direction and moves said first contact meansinto contact with said second contact means, and movement of said memberto said second position swings said fuse in the opposite direction andmoves the first contact means out of contact with the second contactmeans, a mechanism coupled to said member and extending exteriorly ofsaid structure means, said mechanism having ON and OFF positions foroperating the member to its respective first and second positions, saidmechanism including rotatable support means and an operator, saidrotatable support means being rotatable about a first axis from one tothe other of first and second angles, said rotatable support means atsaid first angle barring said door to prevent opening thereof, saidoperator being connected to said member and being supported by saidrotatable support means for rotation about a second axis from one to theother of ON and OFF positions corresponding to the ON and OFF positionsof said mechanism, the second axis being transverse to the first axis,said operator being operable to either ON or OFF positions when therotatable support means is at said first angle, means for preventingoperation of the operator to its ON position when the rotatable supportmeans is at the second angle, means for preventing rotation of therotatable support means to the angle when the second operator is in itsON position, and means responsive to opening of said door for preventingrotation of the rotatable support means from said second to said firstangle.

10. The combination comprising structure means defining interior space,said structure means having an opening and a door therefor movable toclosed and open positions, first switch means including a set ofcontacts dis posed in said space and operable between open and closedpositions and means for operating said contacts, a fuse disposed in saidspace and having one end conductively coupled to one of said contacts,means for rockably supporting said one end of the fuse so that the otherend of the fuse is swingable in opposite directions around said one end,first contact means coupled to said other end of the fuse and movabletherewith, second switch means including said first contact means andstationary second contact means in the path of movement of said firstcontact means, a member movable to first and second positions, means forso coupling said member to said fuse that movement of the member to saidfirst position swings said fuse in one direction and moves said firstcontact means into contact with said second contact means, and movementof the member to said second position swings said fuse in the oppositedirection and moves the first contact means out of contact with thesecond contact means, said structure means having a wall with a slot,and a mechanism coupled to said member and extending through said slot,said mechanism having respective ON and OFF positions for operating saidmember to its respective first and second positions, said mechanismbeing rotatable to first and second angles about an axis, said mechanismbeing reciprocable along said axis between its ON and OFF positions,said mechanism having a portion which moves through said slot when themechanism is operated between its ON and OFF positions, said portionhaving a reduced section which is aligned with said slot when themechanism is in its OFF position, said portion being so dimensioned thatthe walls of the slot interfere with said portion except said reducedsection to prevent rotation of the mechanism around said axis when themechanism is in its ON position, said mechanism having interferencemeans barring said door when the mechanism is at said first angle toprevent opening of the door, said interference means being ineffectiveto bar the door when the mechanism is at said second angle.

ape 33 i9 11. The combination comprising structure means defining aninterior space, said structure means having an opening and a doortherefor movable to closed and open positions, switching means includinga set of contacts disposed in said space and operable between open andclosed positions and means for operating said contacts, a fuse disposedin said space and having one end conductively coupled to one of saidcontacts, means so rockably supporting said one end of the fuse that theother end of the fuse is swingable in opposite directions about said oneend, first contact means coupled to said other end of the fuse andmovable therewith, second switch means including said first contactmeans and stationary second contact means in the path of movement ofsaid first contact means, a member movable to first and secondpositions, means for coupling said member to said fuse in such mannerthat movement of said member to said first position moves said firstcontact means into contact with said second contact means, and movementof said member to said second position swings said fuse in the oppositedirection and moves the first contact means out of contact with thesecond contact means, said structure means having a wall with a slot, amechanism coupled to said member and extending through said slot, saidmechanism having respective ON and OFF positions for operating saidmember to its respective first and second positions, said mechanismbeing rotatable to first and second angles about an axis, said mechanismbeing reciprocable along said axis between its ON and OFF positions,said mechanism having a porton which moves through said slot when themechanism is operated between its ON and OFF position, said portionhaving a reduced section which is aligned with said slot when themechanism is in its OFF position, said portion being so dimensioned thatthe walls of the slot interfere with said portion except said reducedsection to prevent rotation of the mechanism around said axis when themechanism is in its ON position, said mechanism having interferencemeans barring said door when the mechanism is at said first angle toprevent opening of the door, said interference means being ineffectiveto bar the door when the mechanism is at said second angle, and meansresponsive to opening of said door for preventing rotation of saidmechanism from said second to said first angle.

12. The combination comprising an enclosure, said enclosure having anopening and a door therefor with open and closed positions, switch meansincluding a set of contacts disposed in said enclosure and operablebetween open and closed position and first operating means for operatingsaid contacts, a fuse disposed in said enclosure and having one endconductively coupled to one of said contacts, means rockably mountingsaid one end of the fuse to make the other end of the fuse swingable inopposite directions around said one end, first contact means coupled tosaid other end of the fuse and movable therewith, second switch meansincluding said first contact means and stationary second contact meansin the path of movement of said first contact means, a member movablebetween respective OFF and ON positions and coupled to said fuse forswinging said other end of the fuse in one direction about said one endand moving said first contact means into contact with said secondcontact means in response to movement of said member to its ON positionand for swinging said other end of the fuse in the opposite directionabout said one end and moving said first contact means out of contactwith said second contact means in response to movement of said member toits OFF position, said member being disposed in said enclosure, secondoperating means including linkage coupled to said member, said linkagebeing rotatable around and reciprocable along an axis, said secondoperating means further comprising means for rotating said linkagearound said axis from one to the other of first and second angularpositions, means for reciprocating said linkage along said axis from oneto the other of ON and OFF positions when the linkage is at said firstangular position to move said member from one to the other of its ON andOFF positions, means for preventing reciprocation of the linkage whensaid linkage is at said second angular position, said second operatingmeans having interference means preventing the opening of said door whenthe linkage is in the first angular position, and means for preventingrotation of said linkage from its first angular position when thelinkage is in its ON position.

13. The combination comprising an enclosure, said enclosure having anopening and a door therefor with open and closed positions, first switchmeans including a set of contacts disposed in said enclosure andoperable between open and closed position and first operating meanscoupled to said set of contacts for operating said contacts, a fusedisposed in said enclosure and having one end conductively coupled toone of said contacts, means rockably mounting said one end of the fusewhereby in such manner that the other end of the fuse is swingable inopposite directions about said one end, first contact means coupled tosaid other end of the fuse and movable therewith, second switch meansincluding said first contact means and stationary second contact meansin the path of movement of said first contact means, a member movablebetween respective OFF and ON positions, means for so coupling said fuseto said member that movement of the member to its ON position swingssaid fuse in one direction and moves said first contact means intocontact with said second contact means, and movement of the member toits OFF position swings said fuse in the opposite direction and movessaid first contact means out of contact with said second contact means,second operating means including linkage coupled to said member, saidlinkage being rotatable around and reciprocable along an axis, saidsecond operating means further comprising means for rotating saidlinkage around said axis from one to the other of first and secondangular positions, means for reciprocating said linkage along said axisfrom one to the other of ON and OFF positions when the linkage is atsaid first angular position to move said member from one to the other ofits ON and OFF positions, means for preventing reciprocation of thelinkage when said linkage is at said second angular position, saidsecond operating means having interference means preventing the openingof said door when the linkage is in the first angular position, meansfor preventing rotation of said linkage from its first angular positionwhen the linkage is in its ON position, and means responsive to openingof said door for preventing rotation of said linkage from its secondangular position.

14. Switching apparatus comprising a first frame, a second frameslidably mounted in said first frame, a third frame slidably mounted insaid first frame above the second frame, the second and third framesbeing separately slidably removable from the first frame, a set ofcontacts mounted on the second frame and operable between open andclosed position, first operating means mounted on said second frame foroperating said set of contacts, a fuse having one end conductivelycoupled to one of said cont acts, said one end of the fuse beingrockably mounted on said second frame in such manner that the other endof the fuse is swingable in opposite directions around said one end,first contact means coupled to said other end of the fuse and movabletherewith, stationary second contact means in the path of movement ofsaid first contact means, a carrier movable between respective ON andOFF positions and operatively connected to said fuse for swin ing saidother end of the fuse in one direction around said one end and movingsaid first contact means into contact with said second contact means inresponse to movement of the carrier to its ON position and for swingingsaid other end of the fuse in the opposite direction about said one endand moving said first contact means out of contact with said secondcontact means in response to movement of the carrier to its OFFposition, said third frame having means supporting said carrier, secondoperating means coupled to said carrier. and extending outside saidthird frame for moving said carrier from one to the other of its ON andOFF positions, and means for locking said carrier in the ON position inresponse to said first operating means operating said set of contacts totheir closed position.

15. Switching apparatus comprising an enclosure having an opening and adoor therefor with open and closed positions, the door in the closedposition covering a part of said opening, a first frame slidably mountedin said enclosure, said frame being removable through said opening whenthe door is opened, a second frame slidably mounted in said enclosureabove the first frame, the second frame being slidably removable fromthe enclosure through said opening, the second frame having a platewhich is disposed in a portion of the opening not covered \by said doorin its closed position, a set of contacts mounted on the first frame andoperable between open and closed position, first operating means mountedon said first frame for operating said contacts, a fuse having one endconductively coupled to one of said contacts, means for pivotallymounting said one end of the fuse on said first frame in such mannerthat the other end of the fuse is swing-able about said one end firstcontact means cou-. pled to said other end of the fuse and movabletherewith, disconnect switch means including said first contact meansand stationary second contact means in the path of movement of saidfirst contact means, a carrier mounted on said second frame and movablebetween respective OFF and ON positions, means for so coupling said fuseto said carrier that movement of the carrier to its ON position swingssaid fuse in one direction and moves said first contact means intocontact with said second contact means, and movement of the carrier toits OFF position swings said fuse in the opposite direction and movessaid first contact means out of contact with said second contact means,second operating means extending through said plate and includinglinkage coupled to said carrier, said linkage being rotatable around andreciprocable along an axis, said second operating means including meansfor rotating said linkage around said axis from one to the other offirst and second angular positions and means for recipr-ocating saidlinkage along said axis from one to the other of ON and OFF positionswhen said linkage is at said first angular position to move said carrierfrom one to the other of its ON and OFF positions, means associated withsaid second operating means and said plate for preventing reciprocationof the linkage when said linkage is in said second angular position,said second operating means having interference means preventing theopening of said door when the linkage is in the first angular position,means associated with said second operating means and said plate forpreventing rotation of said linkage from its first angular position whenthe linkage is in its OIN position, means responsive to opening of saiddoor for preventing rotation of said linkage from its second angularposition, a member mounted on said second frame and movable betweenfirst and second positions, means for moving said member to its secondposition in response to said first operating means operating said set ofcontacts to their closed position, means responsive to said door beingmoved from its closed to its open position for moving said member to itssecond position, latch means carried by said second frame having alockable latching position which looks the carrier when the latch meansis locked in the latching position, said latch means being locked in thelatching position in response to said member being in its secondposition, said latch means being free of said member when the latter isin its first position.

16. The combination of claim 4 wherein said fuse is generally verticallydisposed with said one end of the fuse below said other end of the fuse,and wherein there is means for supporting said member for generallyhorizontal movement along a line adjacent said other end of the fuse,and said means coupling said member to said fuse includes an articulatedjoint between said member and said first contact means.

17. The combination of claim 5 wherein said fuse is generally verticallydisposed with said one end of the fuse below said other end of the fuse,and wherein there is means for supporting said member for generallyhorizontal movement along a line adjacent said other end of the fuse,and said means for coupling includes a movable joint between said memberand said first contact means.

18; The combination of structure means defining interior space andswitching apparatus mounted in said space, said switching apparatuscomprising a fuse dis-posed in said space, means for supporting saidfuse for substantially pivotable movement of one end of the fuse aboutthe other end of the fuse, first contact means coupled to said one endof the fuse and movable therewith, stationary second contact means inthe path of movement of said first contact means, a member coupled tosaid fuse and movable to first and second positions to swing 'said oneend of the fuse about said other end and move said first contact means,whereby movement of the member to its first position moves said firstcontact means into contact with said second contact means, and movementof the member to its second position moves said first contact means outof contact with said second contact means, said members being disposedin said space, operating means coupled to said member and extendingexteriorly of said structure means for operating the member to itsrespective first and second positions, a movable barrier, and barriermoving means including coupling means connecting said barrier to saidmember for transmitting force from said member to said barrier tointerpose the barrier between said first and second contact means inresponse to movement of said member to its second position and toretract said barrier in response to movement of the member to its firstposition.

19. The combination comprising structure means defining interior space,said structure means having an opening and a door therefor movablebetween closed and open positions, first switch means including a set ofcontacts disposed within said space and operable between open and closedpositions and first operating means for operating said contacts, a fusedisposed within said space and having one end conductively coupled toone of said contacts, means rockably supporting said fuse in such mannerthat the other end of the fuse is swingable in opposite directions aboutsaid one end, first contact means coupled to said other end of the fuseand movable therewith, second switch means including said first contactmeans and stationary second contact means in the path of movement ofsaid first contact means, a member movable to first and second positionsand operatively connected to said fuse for swinging said other end ofthe fuse about said one end and moving said first contact means intocontact with the second contact means in response to movement of themember to its first position and out of contact with the second contactmeans in response to movement of the member to its second position, saidmember being disposed in said space, second operating means coupled tosaid member and extending exteriorly of said structure means, saidsecond operating means having respective ON and OFF positions foroperating said member to its respective first and second positions,means for locking said member in its first position in response to saidfirst operating means operating said set of contacts to its closedposition, and means for locking said member in its second position inresponse to opening of said door.

20. The combination comprising structure means defining inte-rior space,said structure means having an opening and a door therefor movable toclosed and open positions, first switch means including a set ofcontacts disposed within said space and operable between open and closedpositions and operator means for operating said contacts, a fusedisposed within said space and having one end conductively coupled toone of said contacts, means rockably supporting said one end of the fuseto make the other end of the fuse swingable back and forth about saidone end, first contact means coupled to said other end of the fuse andmovable therewith, second switch means including said first contactmeans and stationary second contact means in the path of movement ofsaid first contact means, a member movable to first and second positionsand operatively connected to said fuse for swinging said other end ofthe fuse in one direction and moving said first contact means intocontact with the second contact means in response to movement of themember to its first position and for swinging said other end of the fusein the opposite direction and moving said first con-' tact out ofcontact with the second contact means in response to movement of themember to its second position, said member being dis-posed in saidspace, a mechanism coupled to said member and extending exterionly ofsaid structure means, said mechanism being movable to reposition and thedooris cleared of said interference means whereby the door may beopened, means responsive to the opening of said door for preventingmovement of said mechanism from its SAFE position, a second memberresiliently biased to a first position and movable to a second positionin response to said operator means operating said set of contacts totheir closed position and also in response to said door being moved fromclosed to open position, a latch having a lockable latching position inwhich the latch is locked in response to said second memher being in itssecond position, said first member being locked in its current positionin response to the latch being locked in the latching position.

References Cited by the Examiner UNITED STATES PATENTS 2,629,795 2/1953Hanks 2001 14 2,636,954 4/1953 He-llstern 200114 2,792,472 5/1957 Koch20()133 2,894,085 7/1959 Wilson 200-5015 2,938,093 5/1960 McCloud 200133BERNARD A. GILHEANY, Primdry Examiner.

ROBERT K. SCHAEFER, Examiner.

H. A. LEWITTER, Assistant Examiner.

4. IN COMBINATION, STRUCTURE MEANS DEFINING A SPACE, SAID STRUCTURE MEANS HAVING AN OPENING AND A DOOR THEREFOR OPERABLE BETWEEN OPEN AND CLOSED POSITIONS, FIRST SWITCH MEANS INCLUDING A SET OF CONTACTS DISPOSED IN SAID SPACE AND OPERABLE BETWEEN CLOSED AND OPEN POSITIONS AND OPERATING MEANS FOR OPERATING SAID SET OF CONTACTS, A FUSE DISPOSED IN SAID SPACED AND HAVING ONE END CONDUCTIVELY COUPLED TO ONE OF SAID CONTACTS, MEANS FOR ROCKABLY SUPPORTING SAID ONE END OF THE FUSE IN SUCH MANNER THAT THE OTHER END OF THE FUSE IS SWINGABLE ABOUT SAID ONE END, FIRST CONTACT MEANS COUPLED TO SAID OTHER END OF THE FUSE AND MOVABLE THEREWITH, A SECOND SWITCH MEANS HAVING A SECOND SET OF CONTACTS INCLUDING SAID FIRST CONTACT MEANS AND STATIONARY SECOND CONTACT MEANS IN THE PATH OF MOVEMENT OF SAID FIRST CONTACT MEANS, A MEMBER WHICH IS MOVABLE BETWEEN FIRST AND SECOND POSITIONS, MEANS COUPLING SAID MEMBER TO SAID FUSE IN SUCH MANNER THAT MOVEMNET OF SAID MEMBER TO SAID FIRST POSITION SWINGS SAID FUSE IN ONE DIRECTION AND MOVES SAID FIRST CONTACT MEANS INTO CONTACT WITH SAID SECOND CONTACT MEANS, AND MOVEMENT OF SAID MEMBER TO SAID SECOND POSITION SWINGS SAID FUSE IN OPPOSITE DIRECTION AND MOVES THE FIRST CONTACT MEANS OUT OF CONTACT WITH THE SECOND CONTACT MEANS, AND MEANS FOR LOCKING SAID MEMBER IN SAID SECOND POSITION IN RESPONSE TO OPENING OF SAID DOOR. 